In a cellular phone system, such as a PDC (Personal Digital Cellular telecommunication system), known as an analog cellular system or a digital cellular system, and a PHS (Personal Handyphone System), when a cellular phone or mobile phone device carried by a user receives an incoming call, an alert sound is generated to notify the user of the incoming call. As the alert sound, a beep has been conventionally used, but recently, a music including a melody has come to be used in place of the beep since the beep is offensive to the ear.
A conventional mobile phone device that is capable of reproducing music is equipped with musical composition-reproducing means that is capable of playing automatic performance. The musical composition-reproducing means generally includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a tone generator. The CPU executes an automatic performance program read from the ROM, thereby reading data of a musical composition from the ROM or the RAM, and setting tone generation parameters to the tone generator to reproduce the musical composition.
To reproduce high-quality musical tones, some of the recent mobile phone devices are equipped with musical composition-producing means capable of reproducing a musical composition composed of a plurality of parts.
A mobile phone device is required to be small-sized and lightweight such that it can be conveniently carried by the user, and therefore the space occupied by a battery as a power source of the mobile phone device cannot be increased.
However, when the musical composition-reproducing means performs reproduction of a plurality of parts, high-speed processing is carried out, so that much power is consumed to shorten the battery life.
Further, if the voltage level of the battery is low when the musical composition-reproducing means reproduces a musical composition composed of a plurality of parts, the volume level of the reproduced musical tones lowers to degrade the quality of the reproduced musical tones.
Therefore, it is an object of the present invention to provide a mobile device that is equipped with musical composition-reproducing means and capable of curtailing the battery drain as much as possible, a power saving method therefor, and a storage medium storing a program for executing the method.
Further, it is another object of the present invention to provide a mobile device that prevents the quality of reproduced musical tones from being degraded even if the voltage level of the battery lowers, a volume compensating method therefor, and a storage medium storing a program for executing the method.